Tompkins: Deaths reveal booming sea turtle population

Big recovery evident in losses during freeze

Texas bays are home to more green sea turtles than anyone thought, and perhaps more than in close to a century.

At least they were.

“We knew we had an increasing population of green sea turtles, especially on the lower Laguna Madre around Port Isabel, and we were seeing more in other bays,” said Mike Ray, acting director of Texas Parks and Wildlife Department’s coastal fisheries division. “But I don’t think anyone realized just how many we had.”

Unfortunately, evidence of the expanding green turtle population surfaced in the form of dead turtles.

In the wake of the unusually cold weather that hit the Texas coast Jan. 8-11, scores of cold-stunned green sea turtles were seen floating on the bays or washed onto the bay shore.

The cold-blooded turtles, much like the native fish in Texas bays, have a low tolerance for cold temperatures.

When water temperature drops much below about 50, the turtles begin suffering physiological effects that can prove fatal. They freeze to death.

Over the week following the cold snap, approximately 425 “stranded” sea turtles were found in Texas bays by state and federal wildlife and fisheries staff, conservation groups and private individuals.

“That was a big surprise,” Ray said. “It’s not that we didn’t know they were there — that we had green sea turtles in our bays. But it was the number that was stunning.”

Casualties of the cold

In particular, wildlife and fisheries staffs were amazed at how many green sea turtles turned up along the middle Texas coast. More than 100 dead or cold-damaged green sea turtles were retrieved from East Matagorda Bay in the week following the freeze.

“I don’t think many people realized there were that many turtles in East Matagorda Bay,” Ray said.

The number of dead and cold-injured green turtles seen in the wake of the recent freeze seems to indicate more of the federally- and state-protected turtles are making their home in Texas bays.

In the wake of a brief hard freeze that hit the middle and lower Texas coast in 2006, about 175 cold-stunned or dead green turtles were found along the middle and lower coasts. That was more than were seen after the epic freezes in the 1980s.

“This freeze, we saw more than three times the previous high,” Ray said.

About two-thirds of the turtles recovered over the past two weeks were dead when found. Live but cold-injured turtles were transported to rehabilitation facilities, where many recovered enough to be released back into the bays.

Green sea turtles, the most common of the sea turtles in the Gulf of Mexico, are native to Texas marine waters and once were extremely abundant, particularly along the middle Texas coast.

While adult green turtles, which can weight as much as 800 pounds, spend much of their time in the open ocean, young turtles seem to gravitate to bay environments where they feed mostly on sea grasses and jellyfish.

Vulnerable nearly vanish

“All of the turtles we’ve seen from this freeze were sub-adults,” Ray said.

The turtles were almost extirpated from Texas waters through over-harvest, both in Texas and other warm-water regions frequented by the animals. Sea turtles, which are long lived, don’t reach sexual maturity until 8-10 years old and produce relatively small numbers of offspring, are vulnerable to over-harvest. And that’s what happened to Texas’ sea turtles.

In the late 1800s, a strong commercial turtle fishing industry arose on the middle Texas coast, with turtle processing (canned turtle meat and soup) operations centered on the Aransas and Matagorda bay systems.

The largest turtle processing business was started in 1881 in Fulton, near Rockport. In 1890, that plant processed approximately 250,000 pounds of sea turtles, almost all of them green turtles.

Commercial fishers most often used gill nets to capture the turtles, and in the 1890s, they received about 1 or 2 cents per pound for their catch.

Those commercial fishers often held their catches alive in corral-like structures built of poles shoved into the bay bottom along shorelines.

These “turtle pens” were used until the commercial turtle business collapsed from over-harvest in the early 1900s.

Some of those abandoned pens remained in the bays for years and became landmarks used by anglers and boaters. Although the wooden structures long have disappeared, the site of those in-the-water corrals is still recognized; a handful of spots on bays from East Matagorda Bay to Port Isabel are known as “the turtle pens.”

On the rebound

Decimated sea turtle populations began a slow recovery over the past three decades, thanks to increased protection and a drop in directed commercial harvest outside the United States.

Turtle advocates cite rules mandating use of turtle excluder devices on shrimp trawls operating in U.S. waters as a factor in the recovery.

While the recent loss of 300 green sea turtles to the freezing weather certainly cuts into the population, the toll shows Texas bays are attracting and supporting a growing number of the big marine animals.

By some estimates, the freeze killed more green sea turtles than lived in Texas waters just a couple of decades ago. And an unknown but almost certainly significant number of turtles were not impacted by the cold snap.

“We hate to lose turtles like this,” Ray said of the freeze event. “But the good news is that it shows we have gobs more now than we did just a few years ago.”